Basics Life — buy one get one offer-size is different-unable to exchange-in karaikudi store

Address:

Meher Ali, senior Revenue Inspector,Taluk office, Karaikudi, Sivaganga, Tamil Nadu, 630001

I have purchased t shirts on 06.02.2020 in buy one get one offer. Both the t shirt label shows size is m but one t shirt size is small (T shirt label shows m). I want to exchange that small size t shirt. But karaikudi store not accept me request. He says no exchange in buy one get one offer. I am fully dissatisfied with the service provided to me.